Jackfruit Dodol Drying with Rice Husk Energy in Lombok

Frontiers in Heat and Mass Transfer (FHMT), 17, 15 (2021)
DOI: 10.5098/hmt.17.15
Global Digital Central
ISSN: 2151-8629
Frontiers in Heat and Mass Transfer
Available at www.ThermalFluidsCentral.org
DRYING PERFORMANCE OF JACKFRUIT DODOL USING RICE HUSK
ENERGY ON HOUSEHOLD IN LOMBOK, INDONESIA
Ida Bagus Alit, I Gede Bawa Susana *
Department of Mechanical Engineering, Faculty of Engineering, University of Mataram, Jl. Majapahit No. 62 Mataram-Nusa
Tenggara Barat 83125 Indonesia
ABSTRACT
Rice husk is a cheap fuel source and it is abundantly available in Indonesia. The heat exchanger mechanism was used in other to, the dried material
was not contaminated by the combustion gases. The drying system consists of three components which include the furnace, heat exchanger pipe, and
drying chamber. The heat exchanger pipe connects the furnace with the drying chamber and transfers the heat generated from rice husk burning to the
drying chamber. The drying chamber was the section for drying the jackfruit dodol. It consists of 4 shelves and is equipped with an exhaust fan. The
results showed capable that the dryer decreases moisture faster than conventional methods. The moisture content of jackfruit dodol reduced from 29%
to 23.7% within 600 minutes and the average drying chamber efficiency was 25.3%.
Keywords: dryers, rice husks, heat exchangers, jackfruit dodol
1.
grapes (Sushrut et al., 2015). This forced convectional solar dryer was
discovered to be better in terms of drying speed and quality. Furthermore,
another experimental study was carried out on solar dryers, equipped
with sun tracking to dry apple slices over a temperature range of 62oC
and 45oC (Das and Akpinar, 2020). The disadvantage of this process is
its weather-dependent, thereby being unable to maintain continuous
drying. The utilization of renewable energy such as biomass and the
application of heat exchangers aforementioned is used to solve
conventional agricultural and post-harvest problems. This is because
conventional agriculture is dependent on weather and climate.
Furthermore, the heat exchanger uses the hot air from the burning
biomass in the furnace for the drying process. This device is used to
transmit heat between two fluids separated by a wall and at different
temperatures (Incropera et al., 2006). Biomass, which is an organic
characteristic, derived from living organisms namely plants, animals, and
agricultural wastes is an effective substitute for fossil energy.
Concerning biomass resources, Indonesia has great potential for this
type of renewable energy, particularly rice husk as a rice waste product.
Additionally, rice serves as a food source for most people with the
expectation of fulfilling energy sources, carried out in rural areas through
the energy conversion process such as gasification and pyrolysis. The
gasification technological constitutes of 30% energy conversion used to
produce 49.5 MWh of electrical energy (Pujotomo, 2017). Some of the
location in Indonesia with the potential of biomass energy is West Nusa
Tenggara and Lombok Island produce 533,150.80 and 269,420.20 tons
of rice husks, respectively. It is estimated to produce sufficient energy to
support a power capacity of 60 to 65 MW (RUED Provinsi Nusa
Tenggara Barat, 2019; KPMG, 2019). Rice husk has a high heating value
which is equivalent to half of the coal, namely 12.3 MJ/kg (Awulu et al.,
2018). Its composition includes bulk density of relatively 90 to 150 kg/m3,
lignin (25% to 30%), cellulose (50%), silica (15% to 20%), and moisture
(10% to 15%) (Burhenne et al., 2013; Singh, 2018). It is also a byproduct
of relatively 20% of rice weight and is properly used as an energy source.
INTRODUCTION
Lombok is an Indonesian island located between Bali and Sumbawa.
This is a tourism area with a small industrial centre for processing
plantation products, especially the Jackfruit dodol, which is a traditional
regional cake popular in the community. The fruit is processed into dodol
to increase the sales value as well as extends its shelf life. Furthermore,
the drying process is needed to preserve jackfruit dodol. The drying
process is a method to preserve food ingredients to reduce spoilage and
damage. Generally, this is carried out by placing the product directly
under the sun or by using a dryer, in a drying room. However, both
natural and artificial drying processes involve synchronous heat and mass
exchange between the surrounding air and the granules. Furthermore, this
process tends to reduce the moisture to a minimum level thereby ensuring
its safety before consumption and storage (Delgado-Plaza et al., 2020).
This also needs to be supported by adequate facilities. However, in most
developing countries inappropriate storage and drying facilities tend to
cause post-harvest losses to the agricultural sector (Nguimdo and
Noumegnie, 2020). Therefore post-harvest handling is an important step
adopted to maintain the quality of materials during storage (Buchori et
al., 2013).
Several studies have been widely carried out on drying processes
and ways of handling post-harvest losses. An instance is a gas-to-gas heat
exchanger dryer designed using solid biomass to dry 2.5 kg of palm fiber
(Yunus et al., 2011). The other drying process is anchovy using a heat
exchanger with coconut coir fuel to produce an average temperature of
41.30oC. This heat exchanger consists of pipes that are aligned and
placed separately from the furnace (Susana, 2018). The biomass energy
is often used in the dryer with the natural convection method and
produces hot air at a temperature of 50oC (Bhuyan et al., 2016).
Preliminary research compared forced convectional solar dryer with
natural convection, in a designed collector area of 2 m2 to dry chillies and
*
Corresponding author. Email: [email protected]
1
Frontiers in Heat and Mass Transfer (FHMT), 17, 15 (2021)
DOI: 10.5098/hmt.17.15
Global Digital Central
ISSN: 2151-8629
This is due to the high composition of cellulose which tends to produce
stable combustion. Biomass is used as fuel in the energy conversion
process to dry rice husks at a net calorific value of 12 to 16 MJ kg
(International Finance Corporation, 2017). Furthermore, it is usually
used in rural households for cooking and offering warmth to livestock.
Biomass is also considered waste pollution in the environment therefore,
increased logistics factors and properties are needed to make rice husks
a renewable energy source (Mofijur et al., 2019). The decline in the use
of firewood as fuel due to rice husks decreases deforestation and
maintains sustainability (Ahiduzzaman and Sadrul Islam, 2016).
Meanwhile, the utilization of rice husks in a heat exchanger furnace
offers an optimal drying process.
The furnace converts the stored energy in the rice husks to thermal
energy. The addition of a heat exchanger in the furnace increases the air
temperature in the drying chamber (Susana et al., 2019). This study
utilized black steel pipe as a heat exchanger and rice husks as fuel. In the
no-load condition, the average temperature in the drying chamber was
approximately 72.79oC. Meanwhile, rice husk has a combustion
efficiency of 99.2% and exhibits low emissions, as well as fire
stabilization (Chokphoemphun et al., 2019). This is based on the results
of the test carried out on a rectangular fluidized bed combustor. It also
has LHV and HHV values of 13.3 kcal/kg and 14.8 MJ/kg, which were
obtained based on the measurements carried out on a downdraft furnace
for drying rice (Hung et al., 2018). Furthermore, a direct test was carried
out using rice husks and firewood to boil two litres of water. The result
showed that the time needed to boil 1 kg of rice husk in water is 15
minutes. However, the same quality of rice husk was also boiled for 21
minutes using 1.2 kg of firewood (Yahaya and Ibrahim, 2012). Heat
exchange dryers using rice husk energy are particularly suitable for
household-scale drying processes and in developing rural areas. In the
Philippines, the furnaces fueled by rice husks and heat exchangers with
triangular tubing are used in agricultural engineering standards
(Philippine National Standard, 2015). Meanwhile, those with perforated
walls and the addition of heat exchanger pipes arranged in parallel
optimally transfers heat into the drying chamber (Susana et al., 2019).
The test results showed that it took 58 minutes to reduce the moisture
content of 4 kg of corn from 19% to 12%.
The drying performance of jackfruit dodol using rice husk in
Lombok is still carried out traditionally, by drying in the sun. However,
according to an evaluation result based on the physical parameters, such
as porosity, volume, pore size distribution, and texture, this process
deteriorates the product quality by damaging its structure (Link et al.,
2017). Therefore, based on the sensitivity of certain products, such as
vegetables and fruits, the sun-drying process tends to impair its sensory
and nutritional properties (Ochoa-Martinez et al., 2012). Furthermore,
the high production of rice husks in Lombok Island serves as an energy
source for drying food in rural households, which is optimally carried out
using a dryer. This is performed to enhance the standard of living in these
communities.
2.
400 mm
1. Furnace; 2. Drying chamber; 3. Drying shelves; 4. Exhaust fan; 5. Heat
exchanger pipe; 6. Chimney
Fig. 1 Rice husk dryer design
The dried product is 6 kg of jackfruit dodol. Also, 1.5 kg of this
product was evenly distributed on each shelf. The initial moisture content
of jackfruit dodol was set at 29%. The drying chamber is equipped with
a fan, located in the exhaust pipe or chimney. The air velocity constant
is 2 m/s. The air velocity measurement of 2 m/s is carried out on the
exhaust fan which is placed in the chimney of the drying chamber. The
performance of the dryer is based on the drying temperature and moisture
content of jackfruit dodol. Therefore, this study was carried out using
measuring instruments, such as data loggers, type K thermocouples,
digital scales, anemometers, and moisture meters. The energy source is
in the form of rice husks which transfers heat to the drying chamber
through environmental air flowing in the pipes through combustion, as
shown in Fig. 2.
Fig. 2 Testing of jackfruit dodol samples on rice husk biomass dryer
MATERIALS AND METHODS
The drying performance of jackfruit dodol was carried out for 600
minutes while the moisture content was measured every 60 minutes. The
data measured includes ambient, entry, inner and outer temperatures in
the drying room, as well as the initial, and dry mass of jackfruit dodol.
The initial mass, mt (kg) and dry mass, mk (kg) is used to calculate the
moisture content, Ka (%) (Henderson, 1976; Hamdani et al., 2018), as in
Eq. (1). The heating procedure was carried out for 3 hours at a
temperature of relatively 105 to 110oC to obtain the dry mass of dodol,
mk.
𝑚𝑚 −𝑚𝑚
(1)
𝐾𝐾𝑎𝑎 = 𝑡𝑡𝑚𝑚 𝑘𝑘 𝑥𝑥100%
This research was carried out based on the dryer design and the optimal
temperature test from previous studies (Alit et al., 2020). The optimal
temperature is obtained using a 1-inch diameter heat-transmitting pipe
made of stainless steel material. An 800 mm x 500 mm x 500 mm furnace,
with an iron plate material of 400 mm feet is placed separately from the
drying chamber. The furnace wall consists of 468 holes at a distance of
1 cm and 5 cm respectively. The design of the Jackfruit dodol dryer is as
shown in Fig. 1. The arrangement of the drying chamber comprises 4
shelves made of aluminum. The drying chamber is isolated using a 3 mm
thick rubber material. Furthermore, it has a dimension of 600 mm x 536
mm x 536 mm and the leg height is 400 mm. 400 mm is the support
height of the drying chamber, which is the distance between the floor and
the bottom of the drying chamber.
𝑡𝑡
2
The mass of evaporated water, mw (kg) is influenced by the initial
mass (mt) of the jackfruit dodol, and the mass after drying (mp).
Therefore, Eq. (2) is used to obtain the mass of evaporated water lost due
to the drying process.
(2)
𝑚𝑚𝑤𝑤 = 𝑚𝑚𝑡𝑡 − 𝑚𝑚𝑝𝑝
Frontiers in Heat and Mass Transfer (FHMT), 17, 15 (2021)
DOI: 10.5098/hmt.17.15
Global Digital Central
ISSN: 2151-8629
Fig. 4 shows the temperature distribution that occurs in the jackfruit
lunkhead drying process. The higher the temperature of the hot air that
comes out of the heat exchanger pipes, the higher the drying temperature.
The hot air is the input temperature (Tin) that is used to dry the jackfruit
dodol in the drying chamber. The temperature distribution shown in Fig.
4 follows the process of burning the rice husks in the furnace. At the
beginning of the combustion, the water content of the rice husk was
evaporated. According to Mansaray and Ghaly (1997) that the moisture
content of rice husks ranged from 8.68 to 10.44%. Rice husks undergo a
drying process before further heating occurs. This affects the temperature
which has not increased significantly.
mp is the final mass of the material in each drying process. Obtained
because each drying process will reduce the initial mass of the material
due to the process of evaporation of water on the material or used to
determine the mass of the material after the water has evaporated on
material due to the drying process. While the dry mass (mk) was obtained
by heating using an oven to the material until there was no weight loss
with the treatment carried out at a temperature of 105-110oC for 3 hours.
The heat used for drying, Q (kJ) as in Eq. (3).
(3)
𝑄𝑄 = 𝑄𝑄1 + 𝑄𝑄2
Q1 is the quantity of heat used to dry the material of water (kJ). Q2
is the quantity of heat used to evaporate the moisture (kJ) (Hamdani et
al., 2018; Çengel and Boles, 2006). Cpb is the quantity of specific heat
applied to the jackfruit dodol (kJ/oC), Tb is the jackfruit dodol
temperature (oC), Ta is the ambient temperature (oC), and hfg is the latent
heat of water evaporated (kJ/kg).
Temperature (oC)
(5)
while 𝐶𝐶𝑝𝑝𝑝𝑝 is the
ρu is the density of the drying air
specific heat of the air (kJ/kg.oC). The inner and outer temperatures of
the air are Tin and Tout, respectively. Therefore, the energy transfer from
air to the dried material, q (kJ) is stated as follows (Incropera et al., 2006)
as in Eq. (6).
𝑄𝑄
𝑡𝑡
40
0
100
200
300
400
Time (min)
500
600
700
Rice husks are subjected to burning in the furnace starting from the
bottom to the top. The combustion occurs due to the air flowing into the
heat exchanger pipe and the drying room. The heat transfer from the
burning of rice husk to the exchange pipe in the furnace occurs from the
heat generated by the burning of rice husk outside the heat exchanger
pipe which increases the surface temperature of the pipe. Then heat
transfer occurs from a higher temperature heat exchanger pipe to the
ambient air flowing in the pipe. Heat transfer in the drying chamber to
the dodol occurs from the ambient air which initially flows into the heat
exchanger pipe. This air absorbs heat from the heat exchanger pipes, then
this hot air will flow into the drying chamber for the drying process. The
utilization of environmental air as natural energy will reduce operating
costs (Singh et al., 2019).
In the first 150 minutes, there was an increase in the temperature of
the drying room (Tin). The average intake temperature (Tin) is 86.61oC
which is within the range of 47.43 and 121.19oC. The average ambient
temperature (Ta) is 31.07oC within the range of 28.40 and 32.51oC. The
average exit temperature (Tout) is 49.14oC within the range of 34.23 and
61.49oC. Furthermore, the combustion process spreads upward with the
increase in time until all the rice husks are burned. On the other hand,
there is a decrease in temperature when rice husks are burnt further away
from the heat exchanger pipe, the temperature decreases. Generally, the
temperature of the drying shelves (Ts) and the drying air (Tout) is based
on the inner temperature (Tin). The temperature distribution in the drying
chamber starts from the highest to the least namely shelves 1 (Ts-1), 2
(Ts-2), 3 (Ts-3), and 4 (Ts-4), respectively. The average temperature of
shelf 1 (Ts-1) is 68.16oC, which is within the range of 39.52 and 96.81oC,
while shelf 2 (Ts-2) is 60.76oC between 38.19 and 81.96oC. Furthermore,
the average temperature of shelf 3 (Ts-3) is 55.48oC within the range of
35.55 and 72.84oC, while shelf 4 (Ts-4) is 49.28oC between 34.23 and
61.49oC.
The inner temperature of the drying chamber is uneven on each shelf
due to the obstruction of hot air by the product arrangement and the lack
of air passage to the overhead shelf. Also, the highest drying temperature
occurred on shelf 1 because it is directly related to the heating source.
This is consistent with the previous research carried out by Susana et al.
(2020), which stated that the highest temperature occurred on shelf 1 in
the drying chamber. Table 1 shows the data on temperature and mass
change of jackfruit dodol which is measured every 60 minutes.
(6)
(7)
𝑚𝑚𝑤𝑤
60
Fig. 4 Distribution of drying temperature
The ratio of Eq. (2) to the drying time, t (seconds) is the drying rate,
ṁ p (kg/s) (Brooker et al., 1992; Nazghelichi et al., 2010) as in Eq. (8).
𝑚𝑚̇𝑝𝑝 =
80
0
The drying efficiency is as follows (Çengel and Turner, 2004) as in
Eq. (7).
𝜂𝜂 = 𝑞𝑞 𝑥𝑥 100%
100
20
(kg/m3),
𝑞𝑞 = 𝜌𝜌𝑢𝑢 . 𝑉𝑉𝑢𝑢 . 𝐶𝐶𝑝𝑝𝑝𝑝 (𝑇𝑇𝑖𝑖𝑖𝑖 − 𝑇𝑇𝑜𝑜𝑜𝑜𝑜𝑜 )
Tin
Ts-1
Ts-2
Ts-3
Ts-4
Tout
Ta
120
(4)
𝑄𝑄1 = 𝑚𝑚𝑡𝑡 . 𝐶𝐶𝑝𝑝𝑝𝑝 (𝑇𝑇𝑏𝑏 − 𝑇𝑇𝑎𝑎 )
𝑄𝑄2 = 𝑚𝑚𝑤𝑤 𝑥𝑥 ℎ𝑓𝑓𝑓𝑓
140
(8)
3. RESULTS AND DISCUSSION
The dried jackfruit dodol in this study is shown in Fig. 3 with initial
moisture of 29% and a drying process of 600 minutes.
Fig. 3 The drying results of jackfruit dodol
3
Frontiers in Heat and Mass Transfer (FHMT), 17, 15 (2021)
DOI: 10.5098/hmt.17.15
Global Digital Central
ISSN: 2151-8629
Table 1 Dodol mass and temperature
Time
(min)
Ta (OC)
0
60
120
180
240
300
360
420
480
540
600
29.94
32.19
32.22
32.14
31.88
31.53
31.09
30.75
29.98
29.18
Tin
Drying chamber temperature (OC)
Ts-1
Ts-2
Ts-3
Ts-4
Tout
Jackfruit dodol mass (g)
ms-1
ms-2
ms-3
ms-4
86.51
117.00
118.42
114.39
102.71
83.25
73.18
65.52
55.74
50.16
46.19
57.76
59.46
56.36
53.35
50.79
46.78
45.10
41.19
36.29
46.27
57.68
59.46
56.36
52.81
50.16
46.94
45.02
41.19
36.29
1,487
1,465
1,438
1,409
1,386
1,376
1,369
1,363
1,360
1,358
1,356
53.37
69.26
70.77
66.91
60.21
54.74
51.63
48.54
42.51
37.49
60.64
77.75
78.52
74.17
68.36
60.12
54.40
50.13
44.30
39.73
67.94
91.44
94.45
88.88
77.91
65.23
58.12
52.41
45.37
40.48
The period of 60 minutes is used to reduce the impact of the opening
and closing processes of the chamber because it affects the temperature
distribution process, which started decreasing in the 150 minutes. This is
followed by the phenomenon of burning rice husks.
Fig. 5 shows the changes in the mass of jackfruit dodol on each shelf
in the drying room after 600 minutes. Jackfruit dodol with an initial mass
of ± 6,000 grams (g) and moisture content of 29% was evenly distributed
on each drying shelf ± 1,500 g. The results showed that a longer drying
time causes a decline in mass, which was rapid at the beginning of the
process. The fastest reduction rate occurred on shelf 1 (ms-1) because it
had a higher temperature than others. The decrease in mass on shelves 1
(ms-1), 2 (ms-2), 3 (ms-3), and 4 (ms-4) were approximately 8.8%, 7.2%,
5.99%, and 5.5% respectively. This decrease is based on the drying
temperature distribution pattern with the least found on shelf 4 because
the heat source is farther away from its position.
Moisture content (%)
27
25
23
21
19
Mass (g)
Moisture content (oC)
ms-3
ms-4
1440
1420
1400
1380
0
100
200
300
400
Time (min)
500
600
700
30
29
28
27
26
25
24
23
22
21
20
Day 1
Day 2
Day 3
0
100
200
300
400
Time (min)
500
600
700
Fig. 7 Distribution of jackfruit dodol moisture content in the sun
drying process
1360
1340
Biomass dryer
Sun drying
17
Fig. 6 Comparison of the sun and rice husk biomass used to dry the
moisture content of jackfruit dodol
ms-2
1460
1,507
1,502
1,489
1,471
1,459
1,450
1,442
1,436
1,431
1,427
1,424
29
15
ms-1
1480
1,503
1,496
1,482
1,459
1,445
1,436
1,430
1,423
1,419
1,415
1,413
31
1520
1500
1,501
1,484
1,465
1,442
1,426
1,415
1,411
1,403
1,397
1,395
1,393
Total
mass
(g)
5,998
5,947
5,874
5,781
5,716
5,677
5,652
5,625
5,607
5,595
5,586
0
100
200
300
400
500
600
90
700
80
Temperature (oC)
Time (min)
Fig. 5 Comparison of jackfruit dodol mass with the drying time on each
shelf
Fig. 6 compares the use of rice husk biomass and the sun to dry the
moisture. It showed that the use of rice husk dryers tends to reduce the
moisture faster than the sun. Consequently, within 600 minutes, sun
drying reduced the moisture content from 29% to 26.3%. Meanwhile,
therice husk biomass dryer was able to reduce the moisture from 29% to
23.7%. Sun-drying to reach 23.7% jackfruit lunkhead water content takes
±3 days as shown in Fig. 7. This is caused by a very significant difference
in drying temperature as shown in Fig. 8. Solar drying only utilizes
ambient temperature, while drying in the drying chamber utilizes rice
husk biomass which gives a higher temperature effect. The average
drying temperature of the sun (Tsd) is 31.07oC while the average drying
temperature of rice husk biomass (Tbd) is 58.42oC.
Tsd
Tbd
70
60
50
40
30
20
10
0
0
100
200
300
400
Time (min)
500
600
700
Fig. 8 Comparison of sun-drying temperature (Tsd) with rice husk
biomass drying temperature (Tbd)
The rice husk biomass dryer decreased in moisture content by 0.687
g/min with a chamber efficiency of 25.3%. This condition is influenced
by the drying temperature. The higher the drying temperature is directly
proportional to the faster drying time and vice versa. Longer operating
time is affected by lower temperatures (Bevington and Robinson, 2003).
Besides, this is following the research of Waheed and Komolafe (2019);
4
Frontiers in Heat and Mass Transfer (FHMT), 17, 15 (2021)
DOI: 10.5098/hmt.17.15
Global Digital Central
ISSN: 2151-8629
Dasore et al. (2020) which states that the reduction in drying time is due
to an increase in temperature. Furthermore, rice husks as waste energy
exhibit good results for drying food, as well as an alternative for the
development of energy-efficient dryers (Djaeni et al., 2015). One
kilogram of rice husks (calorific value 15 MJ/kg) is capable of evaporates
4.5 -5.0 kg of water vapour from paddy or shallots.
decrease in moisture contents occurs to shelf 1 (Ka-1) because it is closer
to the drying input temperature. The farther away from the hot air source,
the higher the moisture contents will be. The slowest decrease in moisture
contents occurs to shelf 4 (Ka-4) because its position is farthest from the
heat source.
Changes in the mass of jackfruit dodol are influenced by the
disparity in drying temperature. This is in line with the research carried
out by Alit et al. (2020), which stated that a decrease in the mass of the
dried product is based on the temperature distribution. The dried product
is more hygienic because it is carried out in the drying chamber. This
study is in line with Delgado-Plaza et al. (2020) that drying products
using a dryer minimises animal disturbance and rainy weather conditions
compared to drying in the open sun. The dryer in this study was also
designed to dry food ingredients other than jackfruit dodol. Based on the
results of performance tests on jackfruit dodol, it is estimated that this
dryer can be used to dry other agricultural products such as coffee,
bananas, turmeric, chilli, and other post-harvest products for small
farmers.
30
Ka-1
Ka-2
Ka-3
Ka-4
Moisture content (%)
29
28
27
26
25
24
23
22
21
20
0
100
200
300
400
500
Time (min)
600
700
4.
Fig. 9 Distribution of moisture content (Ka) for each shelf in the
drying chamber
Rice husk is an energy-efficient fuel used for drying household products.
In this research, rice husk was converted to thermal energy using the heat
exchanger process, which is easy to operate and repair by the community.
Based on the sample testing of 6 kg jackfruit dodol at a drying time of
600 minutes, the average drying chamber efficiency was 25.3%. The
dryer tends to reduce the moisture content of dodol from 29% to 23.7%.
The drying process using a biomass dryer is faster than the use of the sun
in Lombok.
100
Ka-1
Temperature (oC)
90
Ka-2
Ka-3
80
Ka-4
70
ACKNOWLEDGEMENTS
60
The authors wish to acknowledge DRPM for funding through the 2021
PTUPT research scheme with contract number 278/E4.1/AK.04.PT/2021
for the first year of research. The author also wishes to thank the
Department of Mechanical Engineering, University of Mataram for
facilitating the implementation of this research.
50
40
30
29.00 27.93 26.58 25.07 23.83 23.27 22.88 22.54 22.37 22.26 22.14
NOMENCLATURE
Moisture content (%)
Cpb
Cpu
hfg
Ka
mk
mp
mt
mw
𝑚𝑚̇𝑝𝑝
Q
Q1
Q2
q
Ta
Tb
Tin
Tout
t
Fig. 10 Comparison of moisture content with temperature on each shelf
1520
1500
1480
1460
Mass (g)
CONCLUSIONS
1440
1420
S-1
S-2
S-3
S-4
1400
1380
1360
1340
20
22
24
26
28
30
Moisture content (%)
Fig. 11 Comparison of mass with moisture content on each shelf
quantity of specific heat applied to the jackfruit dodol (kJ/oC)
specific heat of the air (kJ/kg.oC)
latent heat of water evaporated (kJ/kg)
moisture content (%)
dry mass (kg)
mass of after drying (kg)
initial mass (kg)
mass of evaporated water (kg)
drying rate (kg/s)
heat used for drying (kJ)
quantity of heat used to dry the material of water (kJ)
quantity of heat used to evaporate the moisture (kJ)
energy transfer from air to the dried material (kJ)
ambient temperature (oC)
jackfruit dodol temperature (oC)
inner temperatures of the air (oC)
outer temperatures of the air (oC)
drying time (seconds)
Greek Symbols
𝜌𝜌𝑢𝑢
density of the drying air (kg/m3)
𝜂𝜂
drying efficiency (%)
Fig. 9 presents the distribution of moisture content with drying time
for each shelf in the drying chamber. The fastest decrease in moisture
contents to occur to the highest temperature conditions as shown in Fig.
10. This phenomenon occurs on the four shelves in the drying chamber.
The decrease in water content was followed by a decrease in the mass of
the material as presented in Fig. 11. The highest decrease in the mass of
the material occurred on shelf 1 (S-1) then sequentially occurred on shelf
2 (S-2), shelf 3 (S-3), and the lowest occurred in shelf 4 (S-4). The fastest
REFERENCES
5
Ahiduzzaman, M. and Sadrul Islam, A.K.M., 2016, “Assessment of Rice
Husk Briquette Fuel Use as an Alternative Source of Woodfuel”,
International Journal of Renewable Energy Research, 6(4), 1601-1611.
Frontiers in Heat and Mass Transfer (FHMT), 17, 15 (2021)
DOI: 10.5098/hmt.17.15
Global Digital Central
ISSN: 2151-8629
Hung, N.V., Quilloy, R., and Gummert, M., 2018, “Improving Energy
Efficiency and Developing an Air-Cooled Grate for the Downdraft Rice
Husk Furnace”, Renewable Energy, 115, 969-977.
https://doi.org/10.1016/j.renene.2017.09.012
Alit, I.B., Susana, I.G.B., and Mara, I.M., 2020, “Utilization of Rice
Husk Biomass in the Conventional Corn Dryer Based on the Heat
Exchanger Pipes Diameter”, Case Studies in Thermal Engineering, 22,
1-9.
https://doi.org/10.1016/j.csite.2020.100764
Incropera, F.P., DeWitt, D.P., Bergman, T., and Lavine, A., 2006,
Fundamental of Heat and Mass Transfer, 6th ed., John Wiley & Sons,
New York.
Awulu, J.O., Omale, P.A., and Ameh, J.A., 2018, “Comparative
Analysis of Calorific Values of Selected Agricultural Wastes”, Nigerian
Journal of Technology, 37(4), 1141–1146.
http://dx.doi.org/10.4314/njt.v37i4.38
International Finance Corporation, 2017, Converting Biomass to Energy:
A Guide for Developers and Investors, Pennsylvania Avenue, N.W.
Washington, D.C.
Bevington, P.R. and Robinson, D.K., 2003, Data Reduction and Error
Analysis for the Physical Science, third ed., McGraw-Hill Companies.
KPMG, 2019, Lombok: Prefeasibility Studies on RE Solutions.
Bhuyan, S.K., Rout, H. Pattanayak, B., and Mohapatra, S.S., 2016,
“Performance Investigation of a Natural Convection Grain Dryer for
Paddy Drying”, International Journal of Renewable Energy Research,
6(3), 1050-1056.
Link, J.V., Tribuzi, G., and Laurindo, J.B., 2017, “Improving Quality of
Dried Fruits: A Comparison Between Conductive Multi-Flash and
Traditional Drying Methods”, LWT-Food Science and Technology, 84,
717-725.
https://doi.org/10.1016/j.lwt.2017.06.045
Brooker, D.B., Bakker-Arkema, F.W., and Hall, C.W., 1992, Drying and
Storage of Grain and Oilseeds, 4th ed., Van Nostrad.
Mansaray, K.G. and Ghaly, A.E., 1997, “Physical and Thermochemical
Properties of Rice Husk”, Energy Sources, 19(9), 989-1004.
https://doi.org/10.1080/00908319708908904
Buchori, L., Djaeni, M., and Kurniasari, L., 2013, “Upaya Peningkatan
Mutu dan Efisiensi Proses Pengeringan Jagung dengan MixedAdsorption Dryer”, Reaktor, 14(3), 193–198.
https://doi.org/10.14710/reaktor.14.3.193-198
Mofijur, M., Mahlia, T.M.I., Logeswaran, J., Anwar, M., Silitonga, A.S.,
Ashrafur Rahman, S.M., and Shamsuddin, A.H., 2019, “Potential of Rice
Industry Biomass as a Renewable Energy Source”, Energies, 12(21), 121.
https://doi.org/10.3390/en12214116
Burhenne, L., Messmer, J., Aicher, T., and Laborie, M.P., 2013, “The
Effect of the Biomass Components Lignin, Cellulose and Hemicellulose
on TGA and Fxed Bed Pyrolysis”, Journal of Analytical and Applied
Pyrolysis, 101, 177-184.
https://doi.org/10.1016/j.jaap.2013.01.012
Çengel, Y.A. and Boles, M.A., 2006,
Approach, 5th ed., McGraw-Hill.
Nazghelichi, T., Kianmehr, M.H., and Aghbashlo, M., 2010,
“Thermodynamic analysis of fluidized bed drying of carrot cubes”,
Energy, 35(12), 4679-4684.
https://doi.org/10.1016/j.energy.2010.09.036
Thermodynamics An Engineering
Çengel, Y.A. and Turner, R.H., 2004, Fundamental of Thermal-fluid
Sciences, 2th ed., McGraw-Hill Companies.
Nguimdo, L.A. and Noumegnie, V.A.K., 2020, “Design and
Implementation of an Automatic Indirect Hybrid Solar Dryer for
Households and Small Industries”, International Journal of Renewable
Energy Research, 10(3), 1415-1425.
Chokphoemphun, S., Eiamsa-ard, S., and Promvonge, P., 2019, “Rice
Husk Combustion Characteristics in a Rectangular Fluidized-Bed
Combustor with Triple Pairs of Chevron-Shaped Discrete Ribbed Walls”,
Case Studies in Thermal Engineering, 14, 1-7.
https://doi.org/10.1016/j.csite.2019.100511
Ochoa-Martinez, C.I., Quintero, P.T., Ayala, A.A., and Ortiz, M.J., 2012,
“Drying characteristics of mango slices using the refractance windowtm
technique”, Journal of Food Engineering, 109(1), 69-75.
https://doi.org/10.1016/j.jfoodeng.2011.09.032
Das, M. and Akpinar, E.K., 2020, “Determination of Thermal and
Drying Performances of the Solar Air Dryer with Solar Tracking System:
Apple Drying Test”, Case Studies in Thermal Engineering, 21, 1-15.
https://doi.org/10.1016/j.csite.2020.100731
Philippine National Standard, 2015, Agricultural Machinery-Rice Husk
Fed Heating System-Specifications, PNS/PAES 264.
Pujotomo, I., 2017, “Potensi Pemanfaatan Biomassa Sekam Padi untuk
Pembangkit Listrik Melalui Teknologi Gasifikasi”, Energi dan
Kelistrikan, 9(2), 126–135.
https://doi.org/10.33322/energi.v9i2
Dasore, A., Polavarapu, T., Konijeti, R., and Puppala, N., 2020,
“Convective Hot Air Drying Kinetics of Red Beetroot in thin Layers”,
Frontiers in Heat and Mass Transfer, 14(23), 1-8.
http://dx.doi.org/10.5098/hmt.14.23
RUED Provinsi Nusa Tenggara Barat, 2019, Potensi Limbah
Perkebunan untuk Biomassa, Peraturan Daerah Provinsi Nusa Tenggara
Barat, No. 3.
Delgado-Plaza, E., Quilambaqui, M., Peralta-Jaramillo, J., Apolo, H.,
and Velázquez-Martí, B., 2020, “Estimation of the Energy Consumption
of the Rice and Corn Drying Process in the Equatorial Zone”, Applied
Sciences, 10(21), 1-21.
https://doi.org/10.3390/app10217497
Singh, B., 2018, “Rice husk ash”, Waste and Supplementary
Cementitious Materials in Concrete, 417-460.
https://doi.org/10.1016/B978-0-08-102156-9.00013-4
Djaeni, M., Asiah, N., Suherman, S., Sutanto, A., and Nurhasanah,
A., 2015, “Energy Efficient Dryer with Rice HuskFuelfor Agriculture
Drying”, Int. Journal of Renewable Energy Development, 4(1), 20-24.
http://dx.doi.org/10.14710/ijred.4.1.20-24
Singh, R., Mochizuki, M., Mashiko, K., and Nguyen, T., 2019, “Data
Center Energy Conservation by Heat Pipe Based Pre-Cooler System”,
Frontiers in Heat and Mass Transfer, 13(24), 1-6.
http://dx.doi.org/10.5098/hmt.13.24
Hamdani, Rizal, T.A., and Muhammad, Z., 2018, “Fabrication and
Testing of Hybrid Solar-Biomass Dryer for Drying Fish”, Case Studies
in Thermal Engineering, 12, 489-496.
https://doi.org/10.1016/j.csite.2018.06.008
Susana, I.G.B., 2018, “Improve of Worker Performance and Quality of
Anchovy with Ergonomic Hybrid Solar Dryer”, ARPN Journal of
Engineering and Applied Sciences, 13(5), 1662-1667.
Susana, I.G.B., Mara, I.M., Okariawan, I.D.K.,
Alit, I.B., and
Aryadi, I.G.A.K.C.A.W., 2019, “Ash Hole Variation in Rice Husk
Biomass Furnace with Parallel Flow Heat Exchanger to Drying Box
Henderson, S.M. and Perry, R.L., 1976, Agricultural Process
Engineering, The AVI Pub. Co., Inc., Westport, Connecticut.
6
Frontiers in Heat and Mass Transfer (FHMT), 17, 15 (2021)
DOI: 10.5098/hmt.17.15
Global Digital Central
ISSN: 2151-8629
Temperature”, ARPN Journal of Engineering and Applied Sciences,
14(2), 583-586.
Waheed, M.A. and Komolafe, C.A., 2019, “Temperatures Dependent
Drying Kinetics of Cocoa Beans Varieties in Air-ventilated Oven”,
Frontiers in Heat and Mass Transfer, 12(8), 1-7.
http://dx.doi.org/10.5098/hmt.12.8
Susana, I.G.B., Alit, I.B., and Mara, I.M., 2019, “Optimization of Corn
Drying with Rice Husk Biomass Energy Conversion Through Heat
Exchange Drying Devices”, International Journal of Mechanical and
Production Engineering Research and Development, 9(5), 1023-1032.
https://doi.org/10.24247/ijmperdoct201991
Yahaya, D.B. and Ibrahim, T.G., 2012, “Development of rice husk
briquettes for use as fuel”, Research Journal in Engineering and Applied
Sciences, 1(2), 130-133.
Yunus, Y.M., Al-Kayiem, H.H., and Albaharin, K.A.K., 2011, “Design
of a Biomass Burner/Gas-to-Gas Heat Exchanger for Thermal Backup of
a Solar Dryer”, Journal of Applied Sciences, 11(11), 1929-1936.
https://doi.org/10.3923/jas.2011.1929.1936
Sushrut, S.H., Subbharpurmath, P., Havaldar, N., Hunashikatti, K.,
and Gokhale, S., 2015, “Experimental Analysis of Solar Air Dryer for
Agricultural Products”, International Research Journal of Engineering
and Technology, 2(3), 1517–1523.
7